Coupler with coupling status sensors

ABSTRACT

A coupler ( 24 ) for coupling an accessory ( 28 ) to an excavator arm ( 12 ) of an excavator ( 10 ), the coupler comprising a first jaw ( 30 ) that points in a generally longitudinal direction relative to the frame of the coupler ( 24 ), the jaw ( 30 ) being for receiving a first attachment pin of an accessory ( 28 ) and having a first sensor ( 40 ) for detecting the presence of an attachment pin therein, the coupler ( 24 ) further having a second jaw ( 32 ), or a latch ( 34 ), longitudinally spaced from the first jaw ( 30 ), and being for receiving a second attachment pin of the accessory ( 28 ), and having a second sensor ( 42 ) for detecting the presence of an attachment pin therein. The sensors ( 40, 42 ) transmit or send signals to a receiver ( 46, 48 ) for notifying the driver of the coupling status of the coupler ( 24 ) with respect to the accessory ( 28 ).

The present invention relates to a coupler for remotely attachingaccessories, such as buckets, to an excavator arm of an excavator, e.g.from the cab of the excavator, the coupler being provided with couplingstatus sensors.

Couplers for remotely attaching accessories to an excavator arm of anexcavator are well known per se. However, few such couplers have sensorsbuilt into them. Nevertheless, such couplers, with sensors, are known,and one such coupler is disclosed in EP1318242, to Geith PatentsLimited. That document discloses a coupler with a sensor for detectingwhen the coupler has been moved into a crowd position (i.e. a fullycurled position), and control electronics for permitting the coupler tocommence a decoupling procedure only while the coupler is in that crowdposition. That crowd position is deemed to be a safe position fordecoupling procedures since in that crowd position, the coupler isarranged such that its front jaw is pointing at least partially upwards,whereby an accessory to be attached, or detached, which coupler willalready have an attachment pin located within that front jaw, cannotfall off the coupler even if all other retaining mechanisms for thataccessory are released.

Another prior art coupling system is disclosed in US2004/0244575. Itlikewise looks for the occurrence of the crowd position. However, itdoes so by monitoring for a full extension of one of the excavator arm'shydraulic rams, i.e. the ram that causes the crowd position to occur.

Despite the prior art teachings, however, there is still a possibilitythat a user will misuse couplers by using them, for example, fortransporting accessories without a proper coupling of the accessory ontothe coupler, e.g. by just hooking an attachment pin of an accessory ontothat front jaw without completing the coupling procedure (i.e. byengaging/locking the second attachment pin of the accessory into therear jaw of the coupler). Such improper uses can give rise to dangeroussituations since the attachment can often be shaken out of that frontjaw, or it can be accidentally released from that front jaw if the armand coupler are uncurled. This danger is particularly prevalent giventhat it is not always immediately apparent whether the accessory isproperly attached to the coupler, e.g. upon a user returning to theexcavator after a lunch break, and since the accessories are oftenextremely heavy and large, especially in the mining industries, wherebyan accidental decoupling can present a serious risk of serious injury tothe user and bystanders alike.

The present invention, therefore, seeks to provide a mechanism forpreventing or dissuading a user from engaging in such improper uses ofcouplers.

According to the present there is provided a coupler comprising a firstjaw that points in a generally longitudinal direction relative to theframe of the coupler, the jaw being for receiving a first attachment pinof an accessory, wherein a sensor is provided for that jaw for detectingthe presence of an attachment pin therein.

The sensor may be adapted to output a signal to signify the presence ofan attachment pin in the jaw. Alternatively, or in addition, the sensormay be adapted to output a signal to signify no detected presence of anattachment pin in the jaw.

The sensor's signal may be transmitted or sent to a receiving unit, orto a transmitter, for allowing an indication of the sensed informationto be passed to a user. The transmission may be along a wire, or it maybe wireless, for example a radio transmission. Such wirelesstransmitting technologies are well known in the automobile arts. See,for example, keyless entry systems, tire pressure monitoring systems,and Bluetooth® systems for linking mobile telephones to the vehicle'saudio system.

The user to whom the sensed information is passed, preferably sees,hears or feels the indication while he is within a cab of the excavatorto which the coupler is attached. That receiving unit, or adisplay/indicator mechanism therefor, may therefore be integrated intothe excavator's dashboard. In another arrangement, the receiving unit,or a display/indicator mechanism therefor, may be provided as one ormore separate components for fitting onto or into the excavator, againpreferably within the cab of the excavator. The user, while in the cab,can thus be notified whether an attachment pin is positioned in thatfirst jaw.

The sensor may be a strain sensor. This could detect the presence of anattachment pin within the jaw since accessories, and excavator arms, aregenerally very heavy. Therefore, even if the accessory is resting on theground, the weight of the accessory, or the weight of the arm, willusually cause a force to be applied to the jaw by the accessory'sattachment pin. That force will stress the jaw, thereby creating adetectable strain, perhaps in the throat of the jaw. Therefore, a straingauge located at or in the jaw would be able to detect the presence ofan attachment pin within that jaw.

Other possible sensors might be contact sensors, e.g. PTM (push-to-make)switches. Yet further possible sensors might be magnetic sensors—theattachment pin is usually made of steel. The skilled person willappreciate, however, that numerous different sensors, or combinationsthereof, could be used for detecting the presence, or not, of anattachment pin within the jaw. The advantage of a strain sensor,however, is that it will detect the presence of the attachment pinirrespective of where the pin bears against the jaw, since the stainwill be distributed around the throat of the jaw.

The coupler may also comprise a second jaw, longitudinally spaced fromthe first jaw with respect to the frame of the coupler. That second jawis preferably facing substantially downwards, i.e. approximatelyperpendicularly to the first jaw, and away from the end of the arm ofthe excavator that is attached to the coupler. The second jaw is forreceiving a second attachment pin of the accessory, and it is preferablyassociated with a pivoting or sliding latch for locking that secondattachment pin within that second jaw. In some known couplers, however,just the pivoting or sliding latch is provided—the jaw is omitted.

Preferably a sensor is associated with that second jaw, or the pivotingor sliding latch. That second sensor can be instead of the first sensor,or in addition to the first sensor.

The second sensor is preferably also for detecting the presence of, orthe absence of, an attachment pin. However, that detection is for thesecond jaw, or for the pivoting or sliding latch, instead of the firstjaw.

Preferably the second sensor is mounted directly onto or into to thepivoting or sliding latch, or onto or into that second jaw's alternativelocking mechanism. Locating it into or onto a pivoting or sliding latch,however, is most preferred since most commercial couplers feature eithera pivoting hook or a sliding plate for providing such a lockingfunction.

Preferably the second sensor is a strain gauge. However, any suitablesensor could be provided, as for the first sensor.

The second sensor may have similar or identical features to the firstsensor. However, upon transmitting the signals to the receiving unit,the source of the signals, i.e. with respect to which sensor they camefrom, is preferably discernable by the receiving unit. For transmissionsmade wirelessly, this can easily be achieved by using ID codes in thetransmitted signals, or even by using a single transmitter fortransmitting both sensors' signals in receiver-recognisable manner. Suchcoding technologies are well known in radio transmitting arts, such astyre pressure monitors.

It should also be observed that sensors and transmitters can readily bemade suitably tough to cope with the environments to which couplers areexposed by using designs developed for tyre pressure monitors. Afterall, such prior art systems are designed to cope with high speed tyreenvironments, and the associated forces encountered therein. Therefore,a further discussion of the specific design of suitable sensors andtransmitters is not required herein.

The indicator unit for indicating the sensed information to the user ispreferably in the cab of the excavator. It preferably has visualindicators. They preferably separately provide an indication of thecoupling status of the first and second jaws, i.e. whether there is anattachment pin in the respective jaw. In a simple embodiment, that maybe by means of a light for each jaw. For example, the light for a jawcould be illuminated when an attachment pin is located within therelevant jaw, or perhaps when an attachment pin is not located withinthe relevant jaw. The user can therefore instantly determine theaccessory engagement status of the coupler.

In a preferred embodiment, a green light signifies safety and a redlight signifies danger. Therefore, when both jaws are correctly engagedagainst a pin, i.e. the front jaw's sensor senses the presence of a pin,and the rear latch's sensor also senses the presence of a pin, two greenlights can show on the indicator unit. This indicates a safe mounting ofan accessory on the coupler. However, if only one pin is sensed, a redlight could be illuminated. That would indicate an unsafe mountingcondition.

An alternative arrangement would have a green light show when the firstjaw is correctly engaging a pin, but with a red light showing for thesecond jaw until that second jaw is correctly engaged with the secondpin.

It is possible also to illuminate green lights when no pin is sensed,since the coupler would then not be attached to an accessory, whereby itis safe—there is no risk of an accessory falling off of the coupler.This is useful since couplers typically also feature a lifting eye,which can be used for lifting items with chains or ropes.

A third sensor, and a third light, might also be incorporated into thecoupler at the hydraulic ram. It can sense the location of the latchmechanisms by determination of the state of the ram. That statusinformation can also be transmitted to the receiver for analysis andevaluation. Likewise, a sensor could be provided for sensing theorientation of the coupler.

These and other sensors may be used together with other sensors to builda virtual picture of the condition of the coupler for analysis by acontrol system, which control system can provide suitable warnings tothe user if dangerous conditions are encountered, or simply feedback tothe user to assist with coupling or decoupling procedures since thoseprocedures usually require a number of steps to be undertaken, and thecontrol system could signal to the user when a particular step has beencompleted, e.g. retraction/advancement of the ram, or inversion of thecoupler. See WO2008/029112 or GB0808113.5 for disclosures of variouscoupling and decoupling procedures.

The sensing systems, or the receiver, can be linked to the hydrauliccontrol system of the excavator. With such an arrangement, if an unsafecondition is sensed, the hydraulic system's output can be restricted.For example, the detection of just one attachment pin, e.g. in the first(front) jaw, could cause not just the illumination of a red light on thedisplay unit for the second jaw's sensor, but also a restriction in theoperability of the excavator arm. For example, lifting or swingingmotions might be restricted, prevented or slowed. One such restrictionmight be the provision of a half throttle setting for the hydraulics, orrotation limits for swinging elements. These restrictions could preventunsafe digging activities from being carried out, but without preventingdangerous situations from being recoverable using the hydraulics. A userwould thus be prevented or discouraged for undertaking unsafe workingpractices with the excavator and coupler.

In addition to controlling or limiting the hydraulics usability, theexcavator's manoeuvrability or engine power might also be linked to thesensing system, or to the receiver, whereby they might also berestricted if a dangerous or unsafe accessory condition is sensed. Thiscould be useful since it could additionally prevent movements of theexcavator around a worksite while an accessory is incorrectly mountedonto the coupler. That would further prevent or discourage improperoperator practices, thereby further reducing the possibility for a userto expose himself, or others, to dangerous situations of his own making.

In one embodiment, an additional or separate sensor forms part of awork-tool recognition system. The work-tools for such a system areadditionally provided with a readable or transmittable indicator. Thatindicator might be optically, magnetically, inductively or capacitivelyreadable, or it might be a transmitted signal that can be received andread by the coupler's sensor. Such transmissions can be via wires orthey can be wireless.

In preferred embodiments, the indicator is either a barcode (and thesensor on the coupler is a barcode reader) or an RF (radio-frequency)transmitted signal, which signal might be emitted in response to aninterrogation by a sensor on the coupler, or in response to a circuitbeing completed by the coupling process. Such RF signals wouldpreferably be in the form of a transmitted ID code, or in the form of amore informative signal containing an ID code and some other usableinformation.

The other usable information is preferably indicative or one or more ofthe following parameters: tool type (i.e. bucket, grabber or drill),tool weight or tool capacity (to allow the operator, or the excavatoritself, to know/decide whether the excavator is man enough to handle totool), tool serial number (to allow the specific tool to be tracked),tool age or duty cycle (to allow the operator, or the excavator itself,to know/decide whether the tool is still safe to use, or whether it islikely to suffer a fatigue failure), and tool configuration (e.g.attachment pin size or attachment pin spacing, to allow the coupler toknow whether the tool is mountable onto the coupler).

Likewise, a sensor might be provided on the coupler to read informationfrom the excavator or the excavator arm. For that purpose, the excavatorand/or the excavator arm can be additionally provided with a readableindicator. Similar readable indicators as those that are disclosed abovefor the accessory could be suitable also for the excavator and/or theexcavator arm.

Instead of mounting the additional sensors onto or into the coupler, theadditional sensors might be mounted onto the accessory, or onto theexcavator arm/excavator, with the coupler then having thereadable/transmittable indicator(s).

With these additional sensors and indicators, couplers, excavators andaccessories can be recognised, and thus known limitations of theaccessories, couplers or excavators can be accommodated by the controlelectronics of the excavator. For example, if an accessory such as adrill is attached, the excavator might want to be limited as to how muchlateral force gets applied to the accessory during drilling operations.With such a tool recognition system, such limitations can be imposedautomatically by the excavator's control electronics, thereby reducingthe likelihood of, or preventing, operator error causing severe damageto accessories.

Preferably the sensed information is sent to the excavator's receiverfor processing by the excavator's OEM ECU. That ECU preferably has amemory for storing use information for particular tools or accessories.

Likewise, preferably an ECU is located in the coupler, also with amemory, whereby information as to which accessories and which excavatorshave been attached to the coupler can be stored, or even to allow thecoupler to have its own intelligence for enabling it to refuse to coupleto accessories that fall outside the achievable capacities of thatcoupler, i.e. accessories that are too heavy.

Additional sensors might also be provided in the coupler to sense theloading applied to the coupler during use of an accessory. Those sensorscould be the above-mentioned strain gauges. These could be used to senseoverload conditions in the coupler during such use. Those overloadconditions might be overloading of the coupler, e.g. the jaws or thelatching hook, or of the lifting eye, or they might be overloading ofthe accessory, e.g. where the coupler has recognised the accessory tohave a maximum loading capacity, or a maximum digging/drilling forcecapacity. The coupler could then emit a warning to the operator toinform the operator of that overload condition, or it may signal thatcondition instead to the excavator's receiver/ECU, whereby the excavatorcan impose operational restrictions automatically.

Sensors might also be provided in the coupler, or in the accessory, orin the excavator, to provide coupler/accessory/excavator trackingcapacity, e.g. by the use of GPS sensors, and memorising the identityand location of each accessory/excavator/coupler coupling combination.Then, that stored information might be used to locate specific productsin the future, or for tracking the movement of specific products. Thisallows the movements of a company's fleet and assets to be tracked.Further it can assist in the tracking down of stolen accessories orcouplers.

A specific embodiment of the present invention will now be described, byway of example only, with reference to the accompanying drawings, inwhich:

FIG. 1 schematically illustrates an excavator fitted with a coupler inaccordance with the present invention; and

FIG. 2 schematically illustrates details of that coupler.

Referring first to FIG. 1, there is shown an excavator 10 comprising anexcavator arm 12, a cab 14, an engine area 16, tracks 18 and hydraulicrams 20 for controlling the operation of the excavator arm 12.

A coupler 24 in accordance with the present invention is attached to thefree end 22 of the excavator arm 12. For that purpose, two attachmentpoints 26 (see FIG. 2) are provided on the coupler 24, and twoattachment pins (not shown) extend through those attachment points 26for making the attachment. This type of attachment system isconventional in the art.

An accessory 28 is then attached to that coupler 24. As a result, theexcavator 10, via its excavator arm 12 and hydraulic rams 20, can beused to perform operations with the accessory 28.

In this embodiment, the accessory 28 is a bucket, so normal operationswill be digging.

Referring now to FIG. 2, additional details of the coupler 24 will bedescribed.

The two arm attachment points 26 are positioned in a top portion of thecoupler 24. The bottom portion of the coupler 24 then has the accessoryattachment components. They include a front jaw 30 and a rear jaw 32,each of which will engage attachment pins, but this time on theaccessory 28. For that purpose, the front jaw 30 points substantiallylongitudinally relative to the main axis of the coupler 24 (i.e. towardsthe cab in FIG. 1), whereas the rear jaw 32 points downwardly, i.e.towards the main body of the accessory. As such, the front or first jaw30 can pick up the accessory by hooking onto a first attachment pin ofthe accessory, and the second attachment pin of the accessory can thenbe swung into the open mouth of the rear or second jaw 32. Then, via apivoting latching hook 34, the rear jaw 32 can be closed for securingthe second attachment pin as well. The accessory 28 is thus fullycoupled onto the coupler 24.

The pivoting latching hook 34 is driven into its pin-engaging positionby the coupler's own hydraulic ram 36, i.e. a hydraulic ram 36 that iscontained within the coupler 24.

The above features of the coupler are also all conventional. They arealso interchangeable with alternative mechanisms known in the art. Forexample, additional securement mechanisms can be incorporated into thecoupler, such as in GB2330570 or WO2008/029112. Further, instead of apivoting latching hook 34, a sliding latching plate might be preferred.Likewise, instead of the hydraulic ram 36, a screwthread drive, ormerely a lever-releasable spring could be provided for moving thepivoting or sliding latch 34.

The rear of the coupler 24 is also provided with a lifting eye 38. Thisallows items to be safely hoisted using ropes or chains.

All of the above elements of the illustrated coupler are known orconventional in the art. Therefore, their respective uses andapplications should not need to be discussed further. It should beappreciated, however, that these couplers can be provided in a widerange of sizes, i.e. in sized that are suitable for use with a range ofexcavators.

The inventive features of the present invention are the additionalelements disclosed in the following passages:

The coupler is adapted to include sensing and communicationtechnologies. They serve to provide information to the excavator driverin the cab via a display, although the information might be presentedelsewhere if preferred. The presentation of the information, however,allows the status of the coupler, or of any coupling/decouplingprocedure, i.e. “work tool attachment status” to be communicated to thedriver. Likewise it can be reported to a control system in the excavatorfor providing automated interlocks, which once implemented can preventcertain undesirable or unsafe actions from being carried out by theoperator until an appropriate verification of the coupler's condition orstatus is achieved by the system.

Manual overrides might be provided. However, it would be preferable ifthey could be avoided to ensure that no improper uses can occur.

The provision of such interlocks, or “limp modes”, such as reducesthrottles, or restricted movement ranges, or reduces hydraulic power,will greatly improve workplace safety by preventing or avertingdangerous operations of the excavator, or by minimising or eliminatingmisuse opportunities.

The sensing and communication technologies, in the illustratedembodiment, comprise a selection of sensors, any one of which canprovide a useful and advantageous function in its own right. The firstsensor 40 is a sensor provided for the first jaw 30. It is for detectingwhether an attachment pin is located within that front jaw 30. Thiscould be a proximity sensor, a touch or push actuated sensor or aparameter measuring sensor—e.g. a stress or strain measurement orsensing device. It is shown to be located at the throat of the front jaw30. This is where an attachment pin will typically sit, whereby it willusually be the optimum position. However, it is possible that more thanone sensor, in different positions on that jaw 30, will be necessary toensure that any attachment pin within that jaw can be sensed. This wouldbe of particular value in front jaws having dual-radiused throats (see,for example, Registered Community Design No. 000452271.0003). That isbecause a second sensor in the wall of the larger radiused portion ofthe jaw would allow a large diameter attachment pin, i.e. one whichwould not fit into the back of the throat of the jaw 30, also to besensed.

The optional second, or further sensor 42 is provided for the second orrear jaw 32. In this embodiment it is located in the pivoting latchinghook 34. This second sensor 42 can be identical to the first sensor, inthat it is also for detecting the presence of an attachment pin in itsassociated jaw—the rear jaw 32. By positioning it in the hook, it willonly detect the attachment pin upon the engagement of that attachmentpin by the pivoting latching hook 34. This prevents a false detection ofan unsecured attachment pin. However, if a separate sensor detects thelocation of the hook, that same level of detection could be achievedwith the second sensor being located in the throat of the second jaw.

Again more than one sensor might be provided since different attachmentpins might engage against different parts of the jaw, or againstdifferent parts of the hook, especially where the two attachment pinsare from an accessory that has a different centre-to-centre pin spacing.

The coupler of this exemplary embodiment also has a third sensor 44,which sensor is located within or upon the hydraulic ram 36. It mightlikewise be located within the ram's hydraulic supply-line. This sensorserves to detect either or both hydraulic pressure or hydraulic ramextension status. Such data can serve to allow an even better picture ofthe coupler's status to be determined. For example, it allows theposition of the pivoting latching hook 34 to be checked, or it canidentify a hydraulic fluid leak.

Other sensors, not shown, can include orientation sensors, fordetermining whether the coupler has been inverted, or perhaps to whatdegree it has been inverted. These can be helpful in ensuring that adecoupling procedure is not commenced while the accessory 28 is in anunsafe position relative to the coupler 24, i.e. such that it could fallfrom the coupler if the rear jaw was opened.

Yet further sensors might be provided to identify information from theaccessory themselves, for example from a transponder in the accessory,for detecting accessory type or accessory capacities, which informationcan also be of potential use to a central control unit. That informationcould be stored in the transponder within the accessory.

In the illustrated embodiment, the various sensor components are shownto be integrated into the components of the couplers. As such, thecoupler is bespoke fabricated with the sensors built therein. It shouldbe appreciated, however, that sensors will be incorporatable intoexisting couplers, or known coupler designs, by way of retrofits.Likewise, the associated control electronics, such as those that will befound in the coupler's central control unit 46 in FIG. 2, can be eitherpre-built onto or into the coupler's frame as an integrated part of thecoupler 24, or they might be an aftermarket addition.

In the illustrated embodiment, the first two sensors 40, 42 are adaptedto sense the presence of an attachment pin in their respective jaw orhook, and the third sensor 44 serves to detect the hydraulic pressurewithin the hydraulic ram 36. That sensed data is then eitherintermittently or continuously sent to the associated controlelectronics for analysis, or for transmission to further controlelectronics such as a receiver 48 in the cab. The resulting statusinformation about the coupler is then displayed to the user, or else (orin addition) the data is acted upon by the excavator's own controlelectronics in the appropriate manner, such as by allowing excavatoroperations, or by implementing appropriate “limp modes” for the detectedcoupler status. Numerous possible actions in that regard are possible.For example, the display could have lights signifying good or badconditions for each sensor, such as a green light for a good sensedcondition and red for a bad sensed condition, with the display showingall green lights when an accessory is fully coupled to the coupler, andat least one red light when an accessory is detected to be incorrectlycoupled to the coupler. A limp mode for the excavator would be likely tobe implemented whenever such a red light is indicated.

As indicated above, it will be appreciated that the jaws' sensors shouldbe designed to detect a variety of different attachment pins, such aspins with different radiuses, or different centre-to-centre pinspacings. This is because an excavatore will frequently be used with avariety of different accessories, and not all necessarily from the samemanufacturer—such different accessories often have different pinspacings, or different pin radiuses. Further, attachment pins can becomeworn, whereby the pin spacing between the two pins of an accessory canvary over time.

It will also be appreciated that the sensors should be capable ofhandling, or at least be protected from, the various harsh environmentalconditions that a coupler is likely to be exposed to, such astemperature extremes, regular exposures to abrasive materials such asstones, rocks and mud, rough handling, and also immersion in sea water,fresh water or mud. Such toughened sensor technologies are alreadyavailable, such as from neighbouring fields like tyre pressure monitors.

In one preferred embodiment, the pin sensors 40, 42 in the front andrear jaws 30, 32 are stress or strain sensing sensors. The can detectthe presence of an attachment pin within a jaw since accessories aregenerally very heavy, whereby the jaws will be exposed to significantloading under the weight of an attached accessory. Such stress or strainsensors could therefor detect the presence of an attachment pin by thedetection of such forces. Further, since those forces will beexperienced around the jaw, rather than just at a specific location onthe jaw (i.e. the contact location between the pin and the jaw), thelocation of the sensor is less significant in determining the ability ofthe sensor to achieve its function.

Instead of stress or stain sensors for the first and second sensors,however, proximity sensors might be provided. They could detect theproximity of an attachment pin within the jaws.

In the illustrated embodiment, the three illustrated sensors 40, 42, 44are connected to the central control unit 46 either with wires orwirelessly—the sensors can be wired to the central control unit 46, orthey can have their own radio transmitters built into them. That centralcontrol unit 46 therefore receives the sensed signals from those sensorsand can compile that information ready for transmission to the receiver48 in the cab 14 as intermittent databursts. That receiver 48 is shownto be within the cab of the excavator 10, but it could be elsewhere,with it instead being connected to a display.

The receiver therefore receives the transmissions through a wirelesstransmission such that the receiver can process the sensor data andcause the display or the excavator's control system to actappropriately. The present invention therefore allows the coupler totransmit its own coupler status information reliably to the driver inthe cab of the excavator.

It will be appreciated that transmission and receiver technologiessuitable for such transmissions are well developed in various arts,including tyre pressure monitors. Further, any necessary coding orpairing systems for such transmission/receiver pairs are well developedin those arts. A further discussion of them here is therefore notnecessary.

In place of a wireless transmission to the cab, a wired system could beused to transfer the data. This has the advantage of no local powerbeing needed at the coupler—the sensors could be powered by theexcavator's own power system. However, wireless transmissions arepreferred since they are easier to incorporate into existing excavatorsand couplers—they need minimal setting up, and can readily allowcouplers to be removed from the excavator for servicing.

To power the wireless transmitters, preferably an onboard power systemis provided on the coupler. That could simply be a battery within thecentral control unit 46. However, a generator might be alternatively beprovided on the coupler for generating the required power throughkinetic energy recovery—couplers experience a great deal of shaking whenthey are in use.

Where a battery is provided, a further sensor might be provided tomonitor battery power. The sensor system could therefore also provide alow battery power signal in its transmission when a low battery statusis detected to alert the operator of that fact.

The display or man-machine interface (MMI) in the cab (for indicatingthe sensor information, or coupler status information) can be programmedto provide its information in a number of ways, or just such that itinteracts with the excavator's controls in a number of different ways.

In one system, the signals are translated into visual indicia such aslights or coupler status representations, such that a display can guidethe operator through an accessory coupling or decoupling procedure byproviding graphical indications when certain individual steps of thatcoupling or decoupling process have been achieved. This can be helpfulsince that information is not always possible to see from within the cab(e.g. the position of the pivoting latching hook).

Alternatively, or additionally, the interface can provide excavatorfunctionality lockouts (i.e. “limp modes”) in response to certaindetected situations, such as an incomplete coupling of an accessory tothe coupler (e.g. just in the front jaw). In this regard, specificexcavator or excavator arm movements can be restricted or disabled untilthe coupling procedure has been completed. Alternatively, engine orhydraulic power may be reduced, whereby digging or manoeuvring is mademore difficult. That should dissuade the driver from commencing orcontinuing an improper use of the coupler/excavator.

One preferred feature, however, is that when no attachment pin isdetected, full functionality for the excavator is allowed. That isbecause the coupler is usually fitted with a lifting eye 38, which isoften used for lifting items on a chain or rope. To disable thatfunction would be a significant inconvenience. Further, without suchfreedom to move in an uncoupled condition, manoeuvring the coupler andexcavator to align the front jaw with a first attachment pin of a newaccessory for coupling thereto would also be is made more difficult,which would also obviously be undesirable.

With regard to the limp modes, one such mode could be a low power modein which the throttle is limited to a maximum of a quarter throttle.That could be for either the excavator's engine or just for thehydraulic pump.

It will also be observed that the sensor 44 for the hydraulic ram 36could provide an additional overriding control, whereby in the event ofthe detection of a failure in that hydraulic system, that alone would beenough to cause a limp mode to be effected.

Certain Additionally Optional Features are as Follows:

To enable wireless transmissions to be recognised by the receiver 48,transmissions can be coded with unique identity information that can betransmitted for identifying the coupler/sensors from which thetransmission had originated.

Transmissions could perhaps also include details of the accessory thatis connected to the coupler, e.g. accessory type information. That wouldbe detectable by a sensor on the coupler that can read information froma transceiver on the accessory.

Duty cycle information, such as hours used or cycle completed, might bemonitored by the control system, either at the coupler or at thereceiver. That information could be logged at the coupler andtransmitted to the receiver, or logged at the receiver, wherebyaccessories having a finite duty life can be tracked and repaired orreplaced as and when necessary.

Likewise, other sensed information can be logged or transmitted, such aswork-tool recognition information, excavator recognition information,pairing information, tool suitability information (e.g. tool capacities,types, or sizes), tool or coupler use information (e.g. current loadinginformation), and tracking information (e.g. GPS positioninginformation) for allowing fleet or asset tracking to be automaticallycarried out, or for it to be discernable at a later date from storedinformation.

From the above disclosure, therefore, the present invention provides acoupler for coupling an accessory to an excavator arm of an excavator,the coupler comprising a first jaw that points in a generallylongitudinal direction relative to the frame of the coupler, the jawbeing for receiving a first attachment pin of an accessory and having afirst sensor for detecting the presence of an attachment pin therein,the coupler further having a second jaw, or a latch, longitudinallyspaced from the first jaw, and being for receiving a second attachmentpin of the accessory, and having a second sensor for detecting thepresence of an attachment pin therein. Other features may then be addedto it as described above.

It will also be appreciated that this disclosure also provides forfurther embodiments in which the additional sensors replace one or theother, or both, of the first two sensors. In the most preferredembodiments, however, the sensors of the coupler, or a centraltransmitter, are adapted to transmit or send signals to a receiver fornotifying the driver or operator regarding the coupling status of thecoupler, or the loading status of the coupler, so as to keep the driverinformed as to that status, or in more advanced embodiments, to allowthe excavator to apply operational limitations to the controlelectronics/hydraulics when problems are identified.

Although the present invention has been described above purely by way ofan illustrated example, and by way of possible alternative or additionalfeatures, it will be appreciated that modifications in detail may bemade to the invention within the scope of the claims as appended hereto.

1. A coupler for coupling an accessory to an excavator arm of anexcavator, the coupler comprising a first jaw that points in a generallylongitudinal direction relative to the frame of the coupler, the firstjaw being configured for receiving a first attachment pin of anaccessory and a second jaw longitudinally spaced from the first jaw withrespect to the frame of the coupler, the second jaw being configured forreceiving a second attachment pin of the accessory, the second jawincluding a latch for locking the second attachment pin into the secondjaw of the coupler, wherein a sensor is provided for one of the firstand second jaws for detecting the presence or the absence of anattachment pin in the said first or second jaw and outputting a signalto signify said detected presence or absence. 2.-41. (canceled)
 42. Thecoupler of claim 1, in combination with a receiving unit or atransmitter, wherein signals from the sensor are transmitted or sentalong a wire to the receiving unit, or to the transmitter, for allowingan indication of the sensed information to be passed to a user.
 43. Thecoupler of claim 1, in combination with a receiving unit or atransmitter, wherein signals from the sensor are transmitted or sentwirelessly to the receiving unit, or to the transmitter, for allowing anindication of the sensed information to be passed to a user.
 44. Thecoupler of claim 1, in combination with a display, the display, in use,being located within a cab of the excavator to whose arm the coupler isattached, wherein the sensed information from the sensor is displayed onthe display
 45. The coupler of claim 1, wherein the sensor is one of, ora combination of one or more of, a strain sensor, a PTM (push-to-make)switch, a magnetic sensor, an optical sensor and a capacitance sensor.46. The coupler of claim 1, wherein a second sensor is provided fordetecting one of the presence of an attachment pin in the second jaw,and the presence of an attachment pin in or against the latch.
 47. Thecoupler of claim 46, wherein the second sensor is mounted directly ontoor into a pivoting or sliding latch.
 48. The coupler of claim 1, whereinsignals from the or each sensor are transmittable to a receiving unitwith a coding, whereby the source or sources of the transmitted signals,with respect to which sensor they came from, is discernable by thereceiving unit.
 49. The coupler of claim 1, provided in combination withan indicator unit for indicating sensed information to the user from thecoupler, the indicator unit having a visual indicator for illustratingsensed information, wherein the indicator unit has a light for the firstjaw, the light illuminating when an attachment pin is sensed within thefirst jaw and wherein the indicator unit has a light for the second jawor the latch, the light illuminating when an attachment pin is sensedwithin the said second jaw or latch.
 50. The coupler of claim 49,wherein the indicator also has a light for illuminating when anattachment pin is not sensed.
 51. The coupler of claim 1, furthercomprising an actuator for operating the coupler's latching mechanism,wherein a third sensor is incorporated into or onto the actuator forsensing one of the extension state of the actuator, and, when theactuator is a hydraulic ram that is mounted within the frame of thecoupler, the hydraulic pressure within the ram.
 52. The coupler of claim1, further comprising a sensor of a work-tool recognition system foridentifying information regarding an attached accessory.
 53. The couplerof claim 1, wherein a sensor is provided on the coupler for detecting,in use, a loading applied to a lifting eye of the coupler.
 54. A couplerfor coupling an accessory to an excavator arm of an excavator, thecoupler comprising: a first jaw that points in a generally longitudinaldirection relative to the frame of the coupler, the first jaw being forreceiving a first attachment pin of an accessory; a second jawlongitudinally spaced from the first jaw with respect to the frame ofthe coupler, for receiving a second attachment pin of the accessory, thesecond jaw including a latch for locking the second attachment pin intothe second jaw of the coupler; and an actuator for operating thecoupler's latching mechanism; and a sensor provided on the coupler, thesensor being incorporated either into or onto the actuator for detectingstatus information of the actuator, or into or onto a lifting eye of thecoupler for detecting loading applied to a lifting eye of the coupler.55. A method of notifying to a driver of an excavator the accessoryengagement status of a coupler attached to an end of the excavator'sarm, wherein the coupler is in accordance with claim 1, comprisingsensing an accessory engagement status of the coupler using the or eachsensor and transmitting or sending that sensed information to anotification unit near the driver.
 56. The method of claim 55, whereinone of the sensor system and the notification system is linked to thehydraulic control system of the excavator, whereby if an unsafeaccessory engagement status is sensed, the hydraulic system's output isrestricted.
 57. The method of claim 55, wherein one of the sensor systemand the notification system is linked to the engine management system ofthe excavator, whereby if an unsafe accessory engagement status issensed, the engine's power is restricted.
 58. The method of claim 55,wherein the coupler transmits information regarding the accessoriesand/or excavators to which it is, and/or has been, attached, for receiptby a receiver in or on an excavator.
 59. A method of notifying to adriver of an excavator the accessory status of a coupler attached to anend of the excavator's arm, wherein the coupler is in accordance withclaim 54, comprising sensing an accessory status of the coupler usingthe sensor and transmitting or sending that sensed information to anotification unit near the driver.
 60. The method of claim 59, whereinone of the sensor system and the notification system is linked to thehydraulic control system of the excavator, whereby if an unsafeaccessory status is sensed, the hydraulic system's output is restricted.